Originally signed as an undrafted free agent out of the University of Massachusetts in 2007, safety James Ihedigbo spent his first four NFL seasons with the New York Jets.

Defensive end Shaun Ellis? Their first-round pick (12th overall) out of the University of Tennessee in the 2000 draft, Ellis put in 11 years with the Jets.

This Sunday at Gillette Stadium, the two veterans will suit up against the Jets for the first times in their careers, donning the throwback uniforms of their hated AFC East rivals, the New England Patriots.

“It’s a big game,” Ellis said on Wednesday. “It’s a rivalry game so, of course, regardless of what side of the ball you’re on or what sideline you’re on you want to go out and play your best in this game. It’s one of the biggest rivalries I’ve been a part of since I’ve been in the league.” For more than a decade, he was a member of “Gang Green,” totaling 552 tackles, 721/2 sacks and earning a couple of Pro Bowl berths during that time.

But after being offered the veteran’s minimum $910,000 as a free agent, Ellis felt it was time to move on, agreeing to wear the “Flying Elvis” at a cost of $4 million to his new employer, the deal signed during training camp (Aug. 8).

“I wasn’t hurt (by the Jets’ offer),” said Ellis. “It was just a decision that they made that they wanted to go a different route, so for me it was about putting myself in the best situation. I came here and hopefully we can continue and go on to more successful things.” On an individual basis, Ellis has yet to realize much success with the 3-1 Patriots, his contributions modest at best (four tackles in four starts).

In last Sunday’s 31-19 win at Oakland, the 34-year-old appeared to be in position to make plays and didn’t, the most alarming example coming when he read the play but suddenly appeared to have planted his feet in cement, allowing Jacoby Ford to slip by him on a reverse the wide receiver turned into a 30-yard gain.

That certainly didn’t look like the player who contributed to the Jets’ cause the last time these two teams met, registering two sacks of Tom Brady in New York’s 28-21 win over the Patriots in the teams’ AFC divisional playoff game at Gillette on Jan. 16.

“I definitely have room to improve,” said Ellis. “I’ve got to elevate my game and be more help to our defense. It’s a gradual build(ing) process for me so I just want to go out, continue practicing, working hard, just get my assignments down and just go out there and play” Primarily a special teams player during his time with the Jets, Ihdeigbo has continued in that role (two tackles) while also serving as a backup at safety (four stops) since following Ellis’ path to New England, signing with the Pats on Aug. 19.

Page 2 of 2 - “Anytime you’re playing for a different team, it’s across the league, anytime you go from playing for a team you’re familiar (with) for years and then you go to another team, it does take time to get acclimated, but at the same time that’s kind of the nature of the business we’re in,” Ihedigbo said. “Guys pop around from teams all the time so it’s just making the best of the opportunity that you’re in.

“The opportunity that I have here is great. I love the guys that I’m playing with and you can get a lot of good work done here.” For both players, times have changed, ways of football life have changed.

Rex Ryan’s Jets and Bill Belichick’s Patriots may share a division, but the coaches’ personalities and manners of football operation couldn’t be more diverse: The outspoken Ryan is often as subtle as a crack-back block; Belichick isn’t one to engage in idle talk.

“I don’t want to get into comparisons,” said Ellis. “It’s just totally different. Rex is his way and Bill is his way. So they run two different operations.” Said Ihedigbo: “You can’t really compare them. It’s philosophically two different coaches and (those philosophies) have worked for both sides. Rex will be Rex and Bill will be Bill, and they’re both successful in their own right.”